4) Take an arc at the beginning and end of observing a target, and at ~20 minute intervals on that target.
== '''Troubleshooting & avoiding trouble''' ==
* Do not touch the ''giraffe'' PC while it is busy with a procedure - especially during readout - as QUARTZ is likely to crash.
* If QUARTZ crashes, and complains of a Merlin/transputer error, you will need to go to the Coude room, duck under the coolant pipe, locate the blue Merlin transputer on the shelf below the optical bench and press the ~central red button. Then restart QUARTZ.
* If the orders do not match the requested prism position, initialise the prism with "Find ref" and move to the requested prism position again. You may have to repeat this a couple of times for the prism/camera to reach the requested position.